Perhaps you should try some spelling variations:
trinh han » trinh quan
qua pham » quan pham, quy pham, qua cham
tinh hai » tinh thai, tinh chat, thanh hai
te sach » toc sach
sach tu » sach thu, cach tu, sach ty
tang ma » mang may, tang van
lang xa » lang ha, dang xay, lang van
cua tre » cua te, cuu tre, cua triet

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sach tu ((tang ma) or (lang xa)) hoi. hieu qua pham duc va ((tinh hai) OR (trinh han)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach tu ((tang ma) OR (lang xa)) hoi. hieu qua pham duc va ((tinh hai) OR (trinh han)) cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach tu ((tang ma) or (lang xa)) hoi. hieu qua pham duc va ((tinh hai) OR (trinh han)) cua tre*".